. The First Key Symposium was held in Stockholm, Sweden, 2–5 September 2003. The aim of the symposium was to integrate clinical and epidemiological perspectives on the topic of Mild Cognitive Impairment (MCI). A multidisciplinary, international group of experts discussed the current status and future directions of MCI, with regard to clinical presentation, cognitive and functional assessment, and the role of neuroimaging, biomarkers and genetics. Agreement on new perspectives, as well as recommendations for management and future research were discussed by the international working group. The specific recommendations for the general MCI criteria include the following: (i) the person is neither normal nor demented; (ii) there is evidence of cognitive deterioration shown by either objectively measured decline over time and/or subjective report of decline by self and/or informant in conjunction with objective cognitive deficits; and (iii) activities of daily living are preserved and complex instrumental functions are either intact or minimally impaired.

Autotaxin (ATX) is a tumor cell motility–stimulating factor, originally isolated from melanoma cell supernatants. ATX had been proposed to mediate its effects through 5′-nucleotide pyrophosphatase and phosphodiesterase activities. However, the ATX substrate mediating the increase in cellular motility remains to be identified. Here, we demonstrated that lysophospholipase D (lysoPLD) purified from fetal bovine serum, which catalyzes the production of the bioactive phospholipid mediator, lysophosphatidic acid (LPA), from lysophosphatidylcholine (LPC), is identical to ATX. The Km value of ATX for LPC was 25-fold lower than that for the synthetic nucleoside substrate, p-nitrophenyl-tri-monophosphate. LPA mediates multiple biological functions including cytoskeletal reorganization, chemotaxis, and cell growth through activation of specific G protein–coupled receptors. Recombinant ATX, particularly in the presence of LPC, dramatically increased chemotaxis and proliferation of multiple different cell lines. Moreover, we demonstrate that several cancer cell lines release significant amounts of LPC, a substrate for ATX, into the culture medium. The demonstration that ATX and lysoPLD are identical suggests that autocrine or paracrine production of LPA contributes to tumor cell motility, survival, and proliferation. It also provides potential novel targets for therapy of pathophysiological states including cancer.

Every successful pregnancy requires proper embryo implantation. Low implantation rate is a major problem during infertility treatments using assisted reproductive technologies (ART) 1 . Here we report a new molecular influence on implantation through the lysophosphatidic acid (LPA) receptor LPA 3 2-4 . Targeted deletion of LPA 3 in mice resulted in significantly reduced litter size, which could be attributed to delayed implantation and altered embryo spacing. These two events led to delayed embryonic development, hypertrophic placentas shared by multiple embryos, and embryonic death. An enzyme demonstrated to influence implantation, cyclooxygenase-2 (COX-2) 5 , was downregulated in LPA 3 -deficient uteri during preimplantation. Down regulation of COX-2 led to reduced levels of prostaglandins that are critical for implantation 1 . Exogenous administration of the prostaglandins PGE 2 and cPGI into LPA 3 -deficient females rescued delayed implantation but did not rescue defects in embryo spacing. These data identify LPA 3 receptor-mediated signalling as a new influence on implantation and further indicate linkage between LPA signalling and prostaglandin biosynthesis.Multiple factors can adversely affect successful pregnancy. Two of these factors are failed synchronization between embryonic and endometrial development during implantation and occurrence of multiple gestations (especially monochorionic gestation), which can result in fetal demise 1,6-9 . These factors are particularly important for the clinical success and efficacy of ART. One molecular factor that has been previously implicated in female reproduction is the small, bioactive phospholipid LPA 10 . LPA has a range of influences that are mediated by at least four G protein-coupled receptors, LPA 1-4 2 . Deletion of LPA 1 and LPA 2 in mice revealed roles for these receptors in neural development, craniofacial formation, neuropathic pain, and altered cellular signalling, but without obvious effects on female reproduction 11-Correspondence and requests for materials should be addressed to J. Chun (e-mail:jchun@scripps.edu).. 6 These authors contributed equally to the work. Functional deletion of LPA 3 was achieved by replacing a fragment covering the untranslated region and the start codon in exon 2 with a neomycin-resistance gene in reverse orientation in R1 embryonic stem cells (supplementary Fig. S1). The LPA 3 -deficient mice were born with normal Mendelian frequency without sexual bias (supplementary Table S1), and appeared grossly normal (data not shown). However, LPA 3 -deficient females produced litter sizes of less than 50% compared to that from wild-type (WT) and LPA 3 heterozygote (Het) controls (supplementary Table S2), and showed a statistically significant prolongation of pregnancy (20.9±0.5 days, vs. 19.4±0.7 days in WT/Het controls, P<0.05). These phenotypes were independent of stud genotype, indicating defects in female reproduction. Supplementary InformationTowards determining whether LPA 3 deletion might directly affect the female...

Stimulator of interferon genes (STING) is essential for the type I interferon response against DNA pathogens. In response to the presence of DNA and/or cyclic dinucleotides, STING translocates from the endoplasmic reticulum to perinuclear compartments. However, the role of this subcellular translocation remains poorly defined. Here we show that palmitoylation of STING at the Golgi is essential for activation of STING. Treatment with palmitoylation inhibitor 2-bromopalmitate (2-BP) suppresses palmitoylation of STING and abolishes the type I interferon response. Mutation of two membrane-proximal Cys residues (Cys88/91) suppresses palmitoylation, and this STING mutant cannot induce STING-dependent host defense genes. STING variants that constitutively induce the type I interferon response were found in patients with autoimmune diseases. The response elicited by these STING variants is effectively inhibited by 2-BP or an introduction of Cys88/91Ser mutation. Our results may lead to new treatments for cytosolic DNA-triggered autoinflammatory diseases.

A single-format method to detect multiple G protein-coupled receptor (GPCR) signaling, especially Gα(12/13) signaling, presently has limited throughput and sensitivity. Here we report a transforming growth factor-α (TGFα) shedding assay, in which GPCR activation is measured as ectodomain shedding of a membrane-bound proform of alkaline phosphatase-tagged TGFα (AP-TGFα) and its release into conditioned medium. AP-TGFα shedding response occurred almost exclusively downstream of Gα(12/13) and Gα(q) signaling. Relying on chimeric Gα proteins and promiscuous Gα(16) protein, which can couple with Gα(s)- and Gα(i)-coupled GPCRs and induce Gα(q) signaling, we used the TGFα shedding assay to detect 104 GPCRs among 116 human GPCRs. We identified three orphan GPCRs (P2Y10, A630033H20 and GPR174) as Gα(12/13)-coupled lysophosphatidylserine receptors. Thus, the TGFα shedding assay is useful for studies of poorly characterized Gα(12/13)-coupled GPCRs and is a versatile platform for detecting GPCR activation including searching for ligands of orphan GPCRs.